Glacial Isostatic Adjustment (GIA)

Glacial isostatic adjustment is the ongoing flexing of the solid Earth as it rebounds from the removal of the great ice sheets after the Last Glacial Maximum. The crust under formerly glaciated regions like Scandinavia and Hudson Bay is still rising, while peripheral bulge areas subside, which changes relative sea level independent of ocean volume. GIA models are a required correction when converting tide-gauge and altimetry records into absolute sea-level change and ocean-mass estimates.